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' May'4, 1931. LE ROY H. HOFFER 20348 WELDING MACHINE Original Filed Jan.' 28, 1932 7 Sheets-Sheet 2 Y 1937- LE ROY H. HOFFER v 7 Re. 20,348

I I WELDING MACHINE Original Filed Jan. 28, 1932' T Sheets-Shea}. 3

INVENTOR L E Roy HUI-FER May 4, 1937. LE ROY H. HO'FFER WELDING MACHINE .bri inal Fil ed Jan. 28 1932 I 'TSheets-Sheet 4 A Aw wma c w 7 .m w w in mvNfoR L-E IF Y H. HOFFER May 4, 1937. LE ROY H. HOFFER 20,348

' WELDING MACHINE fJriginal'Filed Jan. 28, 1932 7 Sheefs-Sheeti INVENTOR LE Roy H. HOFFER May '4, 1937. LE ROY H. HOFFVER WELDING MACHINE 7 Sheets-Sheet 6 Original Filed Jan. 28, 1952 INVEN 0 LEfioy H. Home) May 4, 1937. I LE ROY H. HoFFR Re. 20,348 WELDING MACHINE Original Filed Jan. 28, 1932 7 Sheets-Sheet! &

INVENTOR 1E Roy 5. HOFFR Reissued May 4, 1937 i Re,

UNITED STATES PATENT OFFICE WELDING MACHINE Le Roy n. Butter, Brooklyn, N. Y., assignor to Metropolitan Engineering Company, Brooklyn, N. Y., a corporation of New York Original No. 1,968,079, dated July 31, 1934, Serial No. 589,347, January 28, 1932. Application for ,reissue July 18, 1936, Serial No. 91,436

8 Claims. (Cl. 219-4)- The invention provides a machine which is attachments are also taken automatically insucadapted to work rapidly and economically in apcesslon from magazines. Theoperations, how- .p ying a succession of resistance welding operaever, need not'be entirely automatic. One or tions'to a basemember or work piece. I more of them may be taken care of manually.

The accompanying drawings illustrate a ma- In the case illustrated, H is an ordinary welded chine embodying the invention and designed or seamless boiler tube of three or four inchesspeclfically for welding a succession of pins or in diameter and maybe from ten to thirty feet short fins to a boiler tube in two rows extendin length and of a wall thickness of about one lng lengthwiseand located at the opposite Sides quarter of an inch. The attachments I! are fins of the tube. The invention is applicable, howut one quarter of an inch thick. hree-ei hths 10 ever, to the welding of a succession of fins at Wide and one and a hal inc s long- Their one side only, and general-1y to the welding of a er ds e Originally cy d and tapered succession of similar attachments to various other (as shown for example at l3, Fig. 8) and are upproducts. set against the tube to form enlargements l4 Fig. 1' is a perspective view of an end of a. (Fig. 1) at the joint. .These flnsln the ease illus- 15 tube with the fins welded thereon; Fig. 2 is a tr d r sp d very ose together, l v n hall plan and half horizontal section of the maonly sufficient room for individual expansion and chine; Fig. 3 is a half front elevation and half distortion in use. vertical section of the upper part of the ma- The functions f t s p s will p chine; Fig. 4 is a front elevation omitting the ably be clearer if I explain first the succession 20 devices at the sides which apply the attachments; of p r ns through the ro m h i m o Fig. 5 is a vertical transverse section of the same 1. The tube ll rests on a center electrode Fig. 6 is a vertical section approximately on the 1 t is c ampe thereon by a Clamping mline H of Fig. 5, illustrating the mechani her It above carried by a crosshead ll which is for clamping and advancing the tube; Fig. 7 is connected y D rods to lower cross 25 a similar view showing the opposite position of '9 o a p n d Ill Whose p s 2| mov s the clamps; Figs. 8, 9 and 10 are diagrams in t fl y in a cy d c mp e air .plan of the mechanism for handling the attachadmitted to the top or bottom of the cylinder for ments and applying them to the tube; Fig. 11 w ring or raisin th pp cl mpin m er. is'a diagram of the pneumatic and electric cir- The electrode l5 and complementary member is 30 cults controlling the welding operation; Fig. 11 have concave faces to engage the convex conis-an enlarged detail. tour of the tube and embrace the latter between The tube rests on a lower electrode. When them during the wel p it is in position for a welding operation a clamp- The fi s are p as hereina-fter 6X- ing head is brought down on top of it holding plalned in laterally movable electrodes indicated 35 it in position. Attachments are pressed against as a whole by the numeral 23 which are carried it at Opposite sides with a comparatively light on the ends of piston rods 24 of pistms 25 movpressure. The circuit is then closed to pass-a lng laterally in cylinders. 16. Compressed air is I current across the Joints for a certain period. admittedto outer ends of the cylinders o P ss The circuit is then broken and a comparatlvely the-fins against opposite sides of the tube, first 40 high pressure forces the softened attachments with a reduced pressure and finally with an lnagainst the tube to upset the work and complete creased pressure. the weld. The air cylinders are then reversed When the fins are pressed lightly against the p to release the welded attachments from their tube a welding current is passed by closing the holders and withdraw the holders and to lift the circuit from the electrode l5 (which belongs in,

mp h ad m th w rk. At the top of common to both sides) through the tubes to opthe stroke or the clamping head the electrical posite fins l2 and thence to the secondary windcontacts are made whlchcause a repetition of ings 21 of the opposite welding transformers the previous operation. While the clamping head 28. At the end of the operation the air presnit and the attachment holding electrodes sure on the fins is increased to that desired for 50 are withdrawn, the tube is advanced. a step so the upsetting operation after the cutting oil of to b in position to receive the next pair of the current. The electrodes 23 are then unattachments. In the apparatus illustrated this clamped from the-fins and withdrawmby reverse uenc oi operations is automatic and the work 'ing the air presure in their cylinders. The air can be done with exactness and rapidity. The pressure is then reversed in the lower cylinder 55 to lift the upper clamp and permit the tube to be advanced lengthwise in position for the next pair of iins.

High pressure air (say about 108 pounds) is supplied to air pipe 28 through amain valve 38. A branch pipe 3| carries a pressure reducing valve 32 and maintains in the reservoir 33 a supply of air at the lighter pressure (say 15 or,28 pounds).

The air supply to the horizontal cylinders is controlled by valves '34, 35, 38, 31, 38 and; that to the vertical cylinder by valves 48, 4|, 42

and 43. These valves work in one direction by springs and in the opposite direction by solenoids or similar'electrical operating devices. Some of them are normally open (being closed by the solenoids) and others are normally closed (being opened by the solenoids). The normally open valves are indicated by the initials N. O. and the normally closed valves by the initials N. C.. The higher air pressure is applied to the horizontal cylinders only by the opening of the normally closed valves 46 and 41 as will be apparent from the arrangement of the piping. Check,

valves 48 and 48 are provided in order to prevent high pressure from backing up into the low pressure. reservoir 33.

In setting the machine in operation the main air valve 38 is first opened. Then the main switches 58 and 5| of the electric circuits are closed. The main. valve and switches are not changed until all. the fins have been welded on a length of boiler tubing. All the operating cycles follow automatically. The closing of the switch 58 causes a flow of current through the wires 52 and 53, coil 54, wires 55 and 58, contacts 51, 58, wires 58, 68, contacts 6|, 82 and wire 63 to the opposite supply wire 84. The energizing of coil 54 closes the pairs of contacts 55, 88-and 61, 88. The closing of contacts 81, 88 provides an alternate pass or circuit for the current to flow through the coil 54 paralleling the circuit through the contacts 51 and 58; so that when the latter are opened the coil 54 will remain energized.

In a similar way the coil 68 is energized'and controls the circuits through the valves of the welding head on the right hand side of the machine.

The closing of the contacts 85 and 88 closes the circuits through the solenoids of the valves 48, 4|, 42 and 43.- This opens the normally closed valves 48 and 43 so as to cause air to enter. above the piston 2| and to exhaust below the piston;

"and closes the normally open valves 4| and 42.

Thus the piston 2| is forced down, lowering the upper clamping member I8 on the work.

The contacts 51 and 58 tend to spring open, being held and closed by an arm 51 on the cross bar I8 which moves with the lower piston. In the initial downward movement or the piston, therefore, contacts 51 and 58 separate and the circuit through them is broken, the current flowing through the alternate pass provided by the contacts 51, 58 as above explained. At the right side there is a similar'pair of contacts 51, 58 held closed at the top of the stroke by an arm 51".

This arm 51' at the right carries a bar 18 pivoted at its left end .and held up by a light spring and adapted near the end of its downward course to strike a contact 1| which coope ates with a contact 12. Near the end 01' its stroke the bar 18 closes the contacts .1I, 12 for an instant and then passes by, allowing them to spring open'again.

On its upward movement the final upsetting pressure.

it springs past the contacts without effect. These contacts close the circuit through a coil 13 which closes two.

closed valves 34, 36 and 31 which allows low I pressure air to enter the ports 18 and 18 at the rear ends of the cylinders 28 and to exhaust through the ports 88 and 8|. The same circuits close the normally open valves 35, 38 and 38. The air, therefore, advances the pistons 25 and presses the fins 12 against the work with a comparatively light pressure.

The next step is to close the circuits through the transformers. Each'of the electrodes 23 has fastened to its outer end a bar 82 which moves with the electrode and operates certain contacts.

strikes a spring, contact. 84 and holds it 'closed The bar 82 carries a spring retracted prong 83 which, on the advance movement,

momentarily against a mating contact 85, closing the circuit through a; coil 86; the path of the current being from the main conductor 52.

through wire 81, contacts 88, 88, wire 88, contacts 84, 85, wire 8|, coil 88 and wires 82, 83 to the main conductor 84.' The coil 86 closes the pairs of contacts 84, 85 and 88, 81. The circuit through 86, 81 parallels that through the contacts 84', 85 so that when the prong 83 passes these and permits them to separate, the circuit will be maintained through the coil 88. The closing of the contacts 84, 85 closes the circuits through the transformers.

The'welding current continues until the take- ;up of metal at the joint has proceeded to a certain extent. The take-up is measured'by the I travel of the electrodes. The movement of the electrode carries with it the bar 82 which has a projection 88 adapted to strike the upturned end of a. lever arm 88 pivoted at I88 and having 8;43

depending arm I8I which carries the contact 88. The swinging of the arm IM to the left breaks the contact between 88- and 88. This breaks the circuit through the coil 86 and permits the opening of the contacts 84 and 85, which breaks the welding circuit.

' After the welding current is discontinued the high upsetting pressure is to be exerted. As the arm |8I swings to the left it strikes the pin I82 of a whistle valve 46 and opens this high pressure valve. High pressure air then flows into the cylinder through the port 18, giving this electrode An identical operation is'performed through valve 41 and port 18 at the right.

The next step is the reversing of the electrodes and restoring of the machineto its starting posi tion. The movement or the arm I8I breaks the circuit through contacts I83-and I84 located at the lower end of the arm. This breaks the circuit through the coil 13 which causes the opening of the contacts 14 and 15, which breaks the circuit through the valves 34, 35, 38, 31, 38 and 38, causing a reveisal of the movement of the pistons 28. 1 g

when these pistons have moved nearly to their full retracted position the trigger 88 opens the contacts 8|, 82 at one side and a similar device opens the contacts I88, I88 at the other'side; thus ,de-energizing the main coils 54 and 88.

trode holder.

The breaking of the circuit through these coils causes the opening of the contacts 65, 66-and v the contacts 51, 50 and recommence the welding cycle. p

The coil I05 at the right controls the right hand welding head and is controlled in the same way as the coil 96' which controls the left hand welding head. The reason for a separate control by each welding head is that one weld may be completed a fraction of a second ahead of the other. reversing movement of the pistons 25 cannot take placeuntil both sets of contacts I03 and I04 at the left, and I06 and I01 at the right, have been opened by the full advance of the corresponding pistons 25 at the left and right.

The mechanism for clamping the fin in the electrode is shown chiefly in Figs. 2 and 3. The pins I2 are brought down one at ,a time from the magazine and shifted laterally to the positions shown in Figs. 2 and3 resting on the electrode plate H2 carried on a holder H3. Pivoted on the holder is an arm H4 carrying at its forward end a clamping member H5 adapted to bear down on the pin I2. The rear end of the lever H4 is connected to a. link H6 to which is adjustably connected the upper one of a pair of toggle arms III and H0. The arm H8 is pivoted to a downward extension H9 .of the elec- A link I has its forward end connected at III to the two toggle members and its rear end connected to a slide I22 which is actuated by the piston rod 24.

When the piston movesgnward, it first tends to straighten the toggle links H1, H8, which forces down the inner end of the clamping member H4 until the clamp I I5 engages the fin I2. When the toggle links can move no farther, the continued movement of the piston advances the electrode carrier and electrode with the fin until the tapered end of the latter is pressed" against the tube with the air pressure in the cylinder.

A reversing movement of the piston first breaks the toggle and unclamps the fin i2 after the latter has been welded to the tube and then withdraws the electrode carrier and leaves the electrode and clamp clear of theend of the pin,

to permit the tube to be advanced another step.

A new pin is then fed to the electrode as hereinafter described and the cycle repeated.

The downward movement of the clamping member I6, as previously described, holds the tube stationary during the welding operation.

The withdrawal of the clamping member I6 takes place at about the same .time as the withdrawal of the side electrodes.

The step by step advance of the tube between welding operations is accomplished by the following mechanism. The mechanism is actuated by the upward movement of the piston rod 20.

When this rod is in its upper position (Fig. 6),

the clamps I23 are firmly pressed against the tube by means of the levers I24 which are forced apart at their lower ends by the straightening out of the toggle links I25. The levers l24 are fixed on rods I26 which are free to turn and also to slide forward and backward in bearings chine.

With the arrangement shown, the

I2I- (Fig. ,5) at the front and back of the mawith arms I29 pivoted at I30 to a. fixed bracket I3I on the frame I32 of the machine. The arm I29 is part of a bell crank lever whose other arm I33 extends forward and carries a friction roller I34 at its outer end. A tripping lever I35 has a roller I36 which in the raised position of the piston lies above the roller I34. The lever I35 is pivoted at I31 on a forwardly projecting bar I38 which is mounted on top of the cross bar I9 which is carried by the piston rod 20.

As the piston is lowered from the position'of Fig. 5, the roller I36 strikes the roller I34 pressing down the arm I33 and swinging forward the arm I29 and the rods I26. The clamps at this time are inengagement with the tube so that the forward movement of the clamps carries the tube also one step forward.

The tripping lever has a counterweighted arm I39 which in the downward movement strikes a roller I40 mounted in a bracket on the front of the machine. This tilts the lever and allows the roller I36 to ride over the front of the roller I34, releasing the crank lever I33, I29 and ending the forward movement. The rods' I26 and toggles and clamps carried thereby will return Figs. 5 and 6 show the piston at the top of its stroke with the toggle links I25 striking against an adjustable stop I carried by a fixed cross bar I46 so as to regulate exactly the position of the clamps in their engagement with the tube. i

It is desirable to disengage the two clamping rings when inserting a new tube. The raised position of the upper clamp I6 corresponds with the closed position of the side clamps I23. These must, therefore, be released. To effect this, the bracket I44 is mounted to slide vertically on the cross bar I9, the slide having a downwardly extending pin I41 sliding through a bearing I48 carried by the cross bar. A A latch I49 is pivoted to the block I44 and pull the latter down. In

this movement there is first a lost motion in the slots of the loops I43, after which there is a direct pull, down on the toggle pin to break the clamp. after the latch I49 has been withdrawn, the downward movement of the cross bar I9 will be accompanied by a downward movement of the block I44 .until the projecting end of the pin I41 strikes the spring ISI. This spring will hold the pin up as the downward movement of the piston continues until the block I44 is so high above the cross bar I 9 that the latch I49 will drop again into operative position to start work again on a new tube.

Wear on the lower electrode I is saved by lifting the tube slightly when moving it forward. This is accomplished by mechanism shown in Figs. 4 and 5. In the clamped position shown in these figures, a roller I52 bears against the under side of the tube. It is carried at the end of a lever electrode. When the overhead clamp is lifted the weight of the tube is carried to a large extent' (or it may be entirely) by the spring and the sliding movement of the tube has practically no wearing effect on the lower electrode. The projecting ends of the tubes may be supported on any usual or suitable styles of support.

The fins may be fed to the electrodes by the mechanism illustrated in Figs. 8, '9 and 10. The

fins are fed to chutes I6Il (Figs. 2 and 3) at the bottom of which is a receptacle I6I, Figs. 8, 9 and l0, in-which a stack of several fins will lie in approximately horizontal positions. Below the receptacle by a space equal to the thickness of the rounded end of the fin is a stationary plate I62 with an opening I63 therein of approximately the contour of the fin. In a plane between the bottom of the receptacle I6I and the top of the plate -I62 is.a rocking member I64 pivoted at I65.

When it swings from the position of Fig. 8 to that of Fig. 9, it pushes the lowermost fi'n II! from the bottom of the stack over to. the position I2 and drops it through the opening I63 on to the electrode II2 which is spaced below the plate I62 sufficiently to permit the passage of the fin.

The plate II2 has in itsupper face a circular groove I66 in which the cylindrical part I3 of the fin travels, and has shoulders I66 and I66 for holding the fin in its final position on the plate.

I On the plate II2 there is a fiat arm I61 pivoted at I66 and having a forward flange I69 adapted to overlie. the outer end of the fin.

The plate I64 is pivoted on the fixed plate I62 as explained and is connected by a link I16 with the slide II2 so as to advance and retract with the latter. The plate I61, however, is pivoted at I66 on the slide II! and has an arm I1I which is connected by a link I12 to a fixed part of the frame in rear of the slide; so that as the slide advances the plate I61 swings backward and vice versa.

The three Figures 8, 9 and 10 show successive positions of advance. In the first position a fin I2 is held by the shoulders on the electrode plate and by the flange I69. As the electrode slides forward the plate I61 swings backward. In the intermediate position of Fig. 9 the plate I61 underlies the opening I63. By the same movement the plate I64 has been advanced topush a second fin I2 into the opening. The final advanced position is shown in Fig. 10 with the fin I2 in welding position. The plate I61 has been retracted so far as to permit the fin I2 to drop on the plate I I2. In this position the plate I64 holds up the stack of fins in the receptacle I6I. i

Upon withdrawal of the slide, the plate I61 will carry the next fin I2 around to the position of Fig. 8' and hold it there. The plate I64 will at the same time be retracted soas to permit the lowermost fin in the receptacle to drop on to the plate I62 so that on the next advance the previous feeding operation will be repeated.

The attachments bear upon a small area of the tube and under a high pressure, particularly at the endof the welding operation, as explained above in connection with the operation of the welding heads. With tubes of fairly large diam eter and thin walls, there is a tendency to indent the tubes under such pressure. The electrode I5 and top member I6 between which the tube is firmly clamped at the beginning of each welding operation in the zone or portion of its length to which the attachments are to be applied, give the tube strength to resist such local indentations. The clamping members press the tube in opposite vertical directions while the welding headers press the attachments against the tube in opposite lateral directions and the four points to which the pressure is applied are .ln the same zone or ring forming a short portion of the length of the tube. I

What I claim is:--

1. A welding apparatus for applying a plurality of attachments along the length of a tubular work-piece, said apparatus comprising a central electrode adapted to receive the said work-piece, means to clamp the said work-piece thereto in a welding position and to release it at the end of a welding operation, a pair of opposite lateral electrodes, means to advance and retract said lateral electrodes toward and from said work-piece, means to dispose attachments in a position to be engaged by said lateral electrodes and pressed against said work-piece, a second clamping means for said work-piece, means to operate said second clamping means to grip the work-piece between welding operations, means to raise the work-piece from the said central electrode, and

means to advance said second clamping means and the work-piece to a new welding position on said central electrode.

'2. An electric resistance welding machine for applying attachments to a main work-piece inond clamping means to grip the work-piece between welding operations, and means for advancing said second clamping means and the work-piece.

3. An electric resistance welding machine for applying attachments to a main work-piece including in combination means for welding said attachments in succession to the main work-piece, a clamp for holding the work-piece during the weldingv operations, a second clamping means for gripping'the work-piece, mechanism for retracting the first clamp and operating the secondclamping means to grip the work-piece between welding operations, and means for advancing said second clamping means and the work-piece and a device for rendering inoperative the mechanism for operating said second clamping means. 4. A welding apparatus for applying a plurality of attachments along the length of a tubular work-piece at opposite sides in a single passage of the work-piecethrough the machine, said apparatus comprising a central electrode adapted to receive the said work-piece, means to clamp the said work-piece thereto in a welding position and to release it at the end of a welding operation, a pair of oppositelaterai electrodes, means to advance and retract said lateral electrodes toward and from said work-piece, means to dispose attachments in a position to be engaged by said lateral electrodes and pressed against said workpiece, and means ior'advancing the work-piece between welding operations to a new welding position on said central electrode. j

5. A welding apparatus for applying a plurality of attachments along the length of a tubular work-piece at opposite sides in a single passage of the work-piece through the machine, said appara-' tus comprising a central electrode adapted to receive the said work-piece, means to clamp the said work-piece thereto in a welding position and to release it at the end oi a welding operation, a

pair of opposite lateral electrodes, means to advance and retract said lateral electrodes toward and from said work piece, means to dispose attachments in a position to be engaged by said lateral electrodes and pressed against said workpiece and means for removing the work-piece from said central electrode and advancing it between welding operations to a new welding position thereon.

6. A welding apparatus for applying a plurality of attachments along the length of a tubular work-piece at opposite sides in a single passage of the work-piece through the machine, said ap-' paratus including in combination a central electrode adapted to engage such a tubular workpiece, means to engage the work-piece at the opposite side and to clamp it on said electrode in successive 'welding positions, a pairloi opposite lateral electrodes and means ioradvancing them toward the opposite sides of the work-piece said work-piece is clamped on the central electrode so as to press such attachments against-the while opposite sides oi said work-piece at points on its circumference intermediate between the central electrode and said clamping means, and mechanism for releasing said clamping means, withdrawing said lateralyelectrodes and advancing the work-piece between welding operations.

7. A welding apparatus for app yi g a plurality of attachments in two lines lengthwise along opposite sides of a tubular work-piece, said apparatus including in combination clamping devices shaped to engage the contour of such a tubular work-piece at opposite points along a short portion 01' its length and to embrace and hold such portion'in shape dm'ing successive welding operations, means for advancing such attachments and welding them under pressure to the said por-- tionsof the tubular work-piece in successive operations in pairs at opposite sides between said clamping devices, and means for advancing the work-piece to bring successive portions thereof in register with said clamping devices and welding means. 8. A welding apparatus for applying a plurality of attachments in two lines lengthwise along opposite sides of a tubular work-piece, said apparatus including in combination welding heads for pressing attachments substantially simultaneously against opposite sides of the work-piece and passing a welding current w e pressing the attachments against the work-piece and cutting of! the current, said welding means being independently controlled ior cutting oil. the welding current."

' .LE ROY H. HOFFER. 

